Photographic film packages containing a single roll of film installed in a recyclable, lens-fitted camera intended for single use, as typified by the Kodak.degree. "Fun Saver 35.degree.", have gained popularity in recent years for use by photographic enthusiasts on the spur of the moment. Such lens-fitted photographic film packages comprise the elements of a camera fitted with an exposure lens, a simple exposure mechanism which includes a film winding mechanism, a shutter mechanism and a film cartridge or canister, e.g. a standard or special form 35 millimeter cartridge, packaged within the camera which can be sold wherever photographic film is sold for such spontaneous use. Alter the exposure of all frames of the film in the package, it is returned to a photo shop or photo laboratory without removing the film. There, the film package is opened, and the exposed film is developed to make prints therefrom while the paper packaging and mechanism without the film is either scrapped or returned to the manufacturer for recycling. The prints, together with the developed film, are returned to the customer. Such a lens-fitted single use film package makes it easy to take pictures because there is no need for film loading and unloading, and the cost is relatively low. Such single use camera and photographic film packages are disclosed in several forms in U.S. Pat. Nos. 4,831,398, 5054,710 and in Japanese Patent Specification 44-8856.
In those film packages which employ 35 mm film, the filmstrip is withdrawn from the canister or cartridge and pre-wound into a space or film container around a film winding reel during manufacture so that, in use, the filmstrip is advanced back into the canister as each image frame is exposed. It is therefore unnecessary to provide the camera mechanism with a rewind capability which would otherwise increase its cost and complexity.
In the above-cited patents and Japanese specification, the filmstrip leading end or leader is configured to slip into a slit in the shaft of a film spool having a catch or catches formed therein. On insertion during loading of the filmstrip, the filmstrip sprocket hole perforations or other holes in an especially configured leader slip onto the catch or catches. After the camera is closed, the catch or catches engage the filmstrip holes during the pre-wind operation. Typically, the filmstrip is drawn out of its cartridge by a mechanical driver engaging and rotating the end of the shaft exposed through the camera body until the entire filmstrip is wound around the shaft. In certain cases, the end of the shaft is then deformed to prevent it from being driven again. Since in such a case there is no mechanism left to withdraw the filmstrip from the canister and pre-wind it, the camera body cannot be re-filled after use by the average amateur photographer.
The camera mechanisms employed in film packages of this type are typically provided with a thumb actuated film advance wheel or thumbwheel which moves the filmstrip into the film canister one frame at a time, which in turn moves a cam causing a picker to decrement the counter wheel by one count (exposure). The remaining unexposed frames are indicated to the user by the number on the counter wheel appearing in an aperture in the paper packaging overlying the camera mechanism. When the user is ready to take a picture, the film advance thumbwheel is wound in the direction indicated on the package until it stops. In that process, the moving film advances a sprocket which in turn moves a cam causing a picker to decrement the counter wheel by one count. When the last image frame is exposed, the user is instructed to continue to wind the thumbwheel until the counter reads "zero" which ensures that the exposed frames are wound completely into the film canister. In this process, the filmstrip perforations slip off the catch or catches, and the leading end is wound into the light-tight cartridge. Thereafter, the entire film package is submitted to a photo finisher for developing the filmstrip and making prints as indicated above.
As described in commonly assigned U.S. Pat. No. 5,235,366, the photographic film industry is highly competitive, and over the years instances of passing off of counterfeit film canisters have been uncovered. In single use cameras of the type described, it is not possible for a consumer to view the film canister actually installed within the camera mechanism. Consequently, the camera mechanisms and external packaging identifying the genuine manufacturer are all that the consumer has to rely on that the film within the package is genuine. While the manufacturer makes an effort to have photo finishers return the film packages for recycling, the packages may become diverted to others who refill, repackage and resell the film package with counterfeit film at a considerable profit.
The '366 patent discloses one form of a simple mechanism to discourage such unfair competitive acts, and ensure consumers of the quality and reliability they expect to receive when purchasing the branded film package. The circumference of the counter wheel is provided with teeth that engage with the picker rotated by cam the and sprocket except at one location where the tooth is replaced by a solid tab which interferes with the picker such as to shear it off from the cam as the "zero" count is reached. The camera is thus rendered unusable until the cam with an intact picker is replaced in the recycling of the camera after being returned to the manufacturer by the film processor.